oracle net service name resolution -...

Oracle Net Service Name

Resolution

Getting Rid of the TNSNAMES.ORA File!

Simon Pane – Oracle Database Principal Consultant

March 19, 2015

ABOUT ME

• Working with the Oracle DB since version 6

• Oracle Certified Expert

• Oracle Certified Professional– Oracle Database 8, 8i, 9i, 10g, 11g and 12c

• Oracle Certified Partner Specialist

• Oracle ACE Associate

• MOS Communities: Simon_DBA – Level: “Expert”

ABOUT PYTHIAN

10,000Pythian currently manages

more than 10,000 systems.

385Pythian currently employs

more than 385 people in 30

countries worldwide.

1997Pythian was founded in 1997

• Global leader in data consulting and managed services.

• Unparalleled expertise

• Top 5% in databases, applications, infrastructure, Big Data, Cloud, Data Science, and DevOps

• Unmatched certifications

• 8 Oracle ACEs, 2 Oracle ACE Directors, 2 Oracle ACE Associates, 2 Oracle Certified Masters,

• 5 Microsoft MVPs, 1 Microsoft Certified Master

• 1 Cloudera Champion of Big Data

• Broad technical experience

• Oracle, Microsoft, MySQL, Oracle EBS, Hadoop, Cassandra, MongoDB, virtualization,

configuration management, monitoring, trending, and more.

TARGET AUDIENCE

• This presentation is for

– Not Sys Admins

– Not Network Admins

– Not LDAP Admins

NET SERVICE NAME RESOLUTION

A Quick Refresher

WHAT ARE WE TALKING ABOUT?

• Net Service Name– “A simple name for a service that resolves to a connect descriptor”

• Connect Descriptor– “A specially formatted description of the destination for a network

connection. A connect descriptor contains destination service and network route information.”

• The TNSNAMES.ORA file– “The tnsnames.ora file is a configuration file that contains net

service names mapped to connect descriptors for the local naming method, or net service names mapped to listener protocol addresses.”

• Source: https://docs.oracle.com/database/121/NTDBI/glossary.htm

https://docs.oracle.com/database/121/NTDBI/glossary.htm

THE BASICS: THE CONNECT DESCRIPTOR

• Everything could be specified at the prompt

• Good for testing the string/troubleshooting

THE BASICS: EZCONNECT

• 10g added EZCONNECT

– shortened command line specification

THE BASICS: NET SERVICE NAME SEARCH

• Net Service Name can be found in multiple

locations

– TNSNAMES.ORA files, external service, directory

server

– Oracle Net stops searching when it finds the first one

STORING AS UNSTRUCTURED DATA

• “Unstructured” – not in a database

• DNS is somewhat similar yet DNS entries aren’t

stored in host files

• In the TNSNAMES.ORA the “Connect

Descriptors” aren’t consistent in structure or

layout

MANAGEMENT TECHNIQUES

• Scripts that run nightly to “push” out new files to

all servers and desktops

• Centralized files using the TNS_ADMINenvironment variable or soft links

– Storing on a network share or NFS mount

• Centralized using the IFILE parameter

– Can be used up to four times

PROBLEMS WITH THIS APPROACH

• One typo can corrupt the current and all subsequent entries

• Cumbersome to work with/edit with a large number of entries

• If centralized, problems affect all users

• If localized, may take time to propagate changes

• Multiple copies can get out of sync – changes clobbered

“BUT WE'VE ALWAYS DONE IT THAT WAY”

• “Old way” doesn't mean it's the “best way”

WHAT ARE THE OPTIONS

How can we make things better?

ALTERNATIVES

• Store in an “LDAP compatible Directory Server”– Oracle Internet Directory (OID)

– Microsoft Active Directory (AD)

– OpenLDAP

– Others (IBM Tivoli Directory Server, Sun Java System Directory Server, Red Hat Directory Server, Apache Directory Server)

• EZCONNECT

• A hybrid approach using all methods

STRUCTURE IN A “DIRECTORY SERVER”

• Published “LDAP Schema for Oracle Net Services”

• “Structural LDAP Classes” for Oracle Net:orclDBServer

orclNetService

orclNetServiceAlias

orclNetDescription

orclNetDescriptionList

orclNetAddress

orclNetAddressList

orclNetDescriptionAux1

orclNetAddressAux1

CHOOSING A DIRECTORY SERVER

• Easy to install and setup?

• Supported platforms?

• Additional software required?

• Additional hardware required?

• Additional licenses required?

• Bulk load existing entries?

• Easy additions?

• Easy modifications and removals?

• Ability to export to a TNSNAMES.ORA file?

• Supports advanced entries (i.e. TAF, RAC, other options)?

• Supports aliases?

• High availability and protection (backup options)?

• Security implications?

OID BENEFITS

• Complete Oracle stack – full Oracle Support

• Data stored in the Oracle Database– DBAs know how to manage / backup

• High availability options

• Easy TNSNAMES.ORA file generation

• Easy to handle multiple “contexts”– (i.e. .world, .example.com)

OID ISSUES

• Requires a WebLogic domain

– Cumbersome, likely difficult for most DBAs

• May require additional hardware

– For Oracle database repository and/or WLS

• Upgrades and patching (WLS & DB)

• Overkill for just Net Service Name lookup?

ACTIVE DIRECTORY BENEFITS

• Register databases via Oracle Tools (optional)

– DBCA or Oracle Net Manager

• SA handles:

– Replication, HA, Patches, Updates, Backups, etc

• Critical part of the network infrastructure

– Typically high performance

ACTIVE DIRECTORY SETUP

• Very easy to setup (Demo later)

– Requires access to the AD on a DC

– Need Domain Administrator privileges

– Implement using “Oracle Net Configuration Assistant”

and “Oracle Net Manager”

• Follow Oracle Implementation PDF guides

– Follow step-by-step guides:• Configuring Microsoft Active Directory for Net Naming (Doc ID 1587824.1)

https://support.oracle.com/epmos/faces/DocContentDisplay?id=1587824.1

ACTIVE DIRECTORY ISSUES

• Will need cooperation from Domain Admins to install / configure

• Extra AD permissions may be required to query

• 11g Clients:– NAMES.LDAP_AUTHENTICATE_BIND = YES

• Anonymous query may be required for UNIX clients

OPENLDAP BENEFITS

• Free (open-source) Directory Server software

available on a variety of platforms

– Linux, Solaris, MacOS X, Windows, etc

• Master-slave replication options

– Including multiple slaves, cross-platform, cross-

endian

• Easy updates (i.e. yum for Linux deployments)

OPENLDAP INSTALLATION

• Install additional RPMs

– openldap-servers , openldap-clients

• slapd = “stand-alone LDAP directory server”

• Simple initial setup (Demo later)

– Customize some text files; run commands; etc

– Requires some basic Linux skills

– Will need root access

OPENLDAP ISSUES

• No GUI included

– Using with Oracle Net Manager is difficult

• Apache Directory Studio

– Free for Windows, Mac & Linux

COMMON FUNCTIONALITY

• All have (in some form or another)

– Bulk load ability: ldapadd –f <file>

– Command line searching: ldapsearch

– Extraction to a TNSNAMES.ORA file via tool or

command

TOOLS ARE ALREADY INSTALLED!

• LDAP tools in every Database and Client home

WHAT’S THE DOWNSIDE?

Risks, Concerns, Supportability,

Troubleshooting?

WHAT ABOUT SUPPORT?

• With OID the whole stack is supported

• Resolution via AD also supported

• Net Service Name resolution from other

Directory Services not fully supported

– But is that really an issue?

SUPPORT RISKS?

• If using an unsupported Directory Server, DBAs

must know how to investigate/resolve some

problems

– Oracle Support will be limited when investigating

TNS-03505 via SR when not using AD or OID

FAILOVER PERFORMANCE?

• Test failover times from an unresponsive master

server!

• Related MOS notes:– Slow LDAP Naming Resolution when Primary LDAP server unavailable. (Doc ID

1193853.1)

– Performance problem with Oracle*Net Failover when TCP Network down (no IP

address) (Doc ID 249213.1)

– How to Setup LDAP Client Naming Resolution Failover Timeout Against OID - If

OID1 is Busy, Quickly Try OID2. (Doc ID 1671486.1)




BUT REMEMBER…

• Used for initial connection lookup only– Listener sends back a new socket

• Not used again for persistent connections

• Not used for RAC interconnect

• Data Guard & DB Links– Optionally configure with EZCONNECT if support is a

concern

OTHER RISKS?

• Slow / no response from the Directory Servers?

– All options offer redundancy or high availability

– Worst case, switch back to TNSNAMES.ORA

• Some applications may not support it

– Might need some one-off TNSNAMES.ORA files

FUNCTIONALITY RISKS?

• Extra complexity with advanced options

– TAF entries, RAC entries, global_name

– Oracle Net aliases

• Oracle7 and Oracle8.0 clients

– Still can be done but requires extra/different steps

DEBUGGING TECHNIQUES: TRACING

• Oracle Net (SQL*Net) Tracing– HOWTO : Use sqlnet tracing to track down which tnsnames.ora file is used

in the connection? (Doc ID 846822.1)

– How to Enable Oracle SQLNet Client , Server , Listener , Kerberos and

External procedure Tracing from Net Manager (Doc ID 395525.1)

• Oracle whitepaper on interpreting the result– Examining Oracle Net, Net8, SQL*Net Trace Files (Doc ID 156485.1)

• Trace Assistant– Example of Using Trace Assistant (TRCASST) to Work an Oracle Net issue (Doc

ID 1336069.1)





DEBUGGING TECHNIQUES: TRCROUTE

• Oracle Trace Route utility

– Reports on TNS entries on route to the “server”– https://docs.oracle.com/database/121/NETAG/connect.htm#NETAG383

https://docs.oracle.com/database/121/NETAG/connect.htm#NETAG383

DEBUGGING TECHNIQUES: OS TOOLS

• Linux

– Strace:

• $ strace tnsping ORCL

• Windows

– Windows Sysinternals Process Monitor:

• Run in batch file with command line switches

– NtTrace:

• http://www.howzatt.demon.co.uk/NtTrace

http://www.howzatt.demon.co.uk/NtTrace

THINGS TO WATCH OUT FOR

• NAMES.DIRECTORY_PATH– Methods not specified are excluded

– Also determines search order

– Must keep EZCONNECT for RAC cluster interconnect

• Files searched– Remember: /etc/tnsnames.ora– Hidden file: ~/.tnsnames.ora

• Windows– Different search order rules (cwd vs. home dir)

– Different search orders if %ORACLE_HOME% is set

VIRTUAL DEMO 1

OpenLDAP setup on OL6.5

In 10 simple steps!

DEMO1: OpenLDAP SETUP

• STEP 1: Install the required RPMs


• STEP 2: Some basic initial setup

• STEP 3: Set the LDAP admin password

– Record the hash for use later


• STEP 4: Create a default configuration file

• STEP 5: Create the OID schema files


• STEP 6: Edit /etc/openldap/slapd.conf

– Add new OID schema files

– Update all occurrences of “my-domain”

– Add rootpw hash value (could use plain text as well)


• STEP 7: Start and register slapd service

• STEP 8: Manually add the OU to the root


• STEP 9: Add the orclContext and the first

entry


• STEP 10: Adjust SQLNET.ORA & LDAP.ORA


• Additional optional steps

– Add master and slave(s) replication (HA)

– Secure with TLS and a certificate

– Configure Apache Directory Studio

– Script simplified additions using ldapadd

– Script TNSNAMES.ORA generation using ldapsearch

VIRTUAL DEMO 2

Active Directory Setup

In < 10 simple steps!

DEMO 2: ACTIVE DIRECTORY SETUP

• STEP 1: Follow steps provided in Oracle PDF

• Configuring Microsoft Active Directory for Net Naming (Doc ID 1587824.1)



• STEP 2: Adjust SQLNET.ORA & LDAP.ORA


• STEP 3: Add an entry

– Using the Oracle Net Manager utility on the DC

– Under the “Directory” tab


• STEP 4: Verify the entry

– Using “Active Directory Users and Computers”


• STEP 5: Verify that the entry can be modified

– Using “Active Directory Explorer” (Sysinternals)


• STEP 6: Test that data can be extracted

– Using “ldapsearch”


• STEP 7: Test resolution from Windows


• STEP 8: Test resolution from Linux

WRAP UP!

SUMMARY 1

• OID, Active Directory, and OpenLDAP are all just

three out of many possible LDAP Directory

Servers software products

• Oracle “Connect Descriptors” can be stored and

accessed from any LDAP Directory Server

• Active Directory and OpenLDAP are the easiest

to setup

SUMMARY 2

• Initial data can be bulk loaded

• Data can be extracted to a TNSNAMES.ORA

• Simple scripts can be used to automate:

– Creation of new entries

– Extraction into a TNSNAMES.ORA

• LDAP utilities are already in every $OH

SUMMARY 3

• Cost is typically a few days of initial setup work– Include setup and procedural documentation!!!!

• Deployment risk is minimal– As hybrid approach can be used

• Lower risk of issues if stored in a proper Directory Service– Reduced propagation time for additions/changes

– Lower chance of introducing a widespread error

– Higher availability

THANKS AND Q&A

[email protected]

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